The most common prostheses used to restore a damaged tooth crown are full artificial crowns. Due to the fact that they have different designs and are intended for different purposes, they are systematized according to certain criteria:

I. By design or by size and method of enveloping the tooth:

1) complete, that is, covering all surfaces of the tooth;

2) equatorial, that is, reaching the equator of the tooth;

3) crowns with a pin;

4) telescopic crowns;

5) fenestrated or fenster crowns.

II. By manufacturing method:

1) stamped;

3) soldered (suture) - now practically not used.

III. Depending on the material:

1) metal (gold alloys, stainless steel, cobalt-chrome alloys (CHS), silver-palladium, titanium);

2) non-metallic (plastic, porcelain);

3) combined, that is, lined with plastic, porcelain or other ceramic masses (metal-plastic and metal-ceramic).

IV. By purpose:

1) restorative;

2) supporting (in bridges or other types of prostheses);

3) fixing (for holding medications, orthodontic or maxillofacial devices);

4) splinting;

5) temporary and permanent.

Indications for the use of crowns:

1. An absolute indication for the use of artificial crowns is significant tooth destruction due to caries, its complications or other causes. That is, in other words, the indications are those defects in the crowns of the teeth that cannot be eliminated with a filling or inlay.

2. In some cases, metal crowns are used to cover teeth that serve as supports for clasps, especially if it is necessary to change their clinical shape.

3. For fixation during treatment with bridges, that is, supporting crowns.

4. In case of pathological abrasion to prevent the development of further abrasion.

5. With abnormal shape, color, structure of teeth.

6. For attaching various orthodontic or maxillofacial devices.

7. For splinting in case of periodontal diseases and jaw fractures.

8. To hold medicines.

9. Aesthetic indications (porcelain, plastic and combined crowns).

Contraindicated Covering intact teeth with crowns should be considered if this is not caused by the design features of dentures. You should not cover with crowns teeth with untreated foci of chronic inflammation in the region of the marginal or apical periodontium, teeth with severe pathological mobility (III degree according to Entin); in poor general health.

With the help of artificial crowns, the original anatomical shape of damaged teeth is restored or a new, appropriate shape is created, taking into account the optimal functional and static requirements for intact teeth.

According to their purpose they are divided into:

• 1) restorative;
• 2) protective, or contour;
• 3) supporting;
• 4) orthodontic.

Restorative crowns serve to compensate for large defects in the crown of the tooth. They are used in cases where therapeutic dentistry cannot compensate for a defect in hard tissues, and there are no necessary conditions for the use of inlays. Suture, stamped, cast, porcelain, plastic and combined crowns are used as restorative crowns, i.e. all types of crowns that completely cover the prosthetic teeth*. Half-crowns are not used for this purpose.

Contour protective crowns are intended to cover teeth on which clasps are applied to secure partial dentures. These crowns protect the enamel of the corresponding teeth from destruction by clasps, and also give the supporting tooth the most appropriate shape for applying a clasp. Protective crowns improve the cosmetic properties of removable partial dentures because the clasp is hardly noticeable against the background of the protective crown if they are made of the same metal.

Abutment crowns serve to fix bridges on teeth that limit the defect of the dentition. They are soldered or cast together with the phantom part of these prostheses and provide support for them.

Orthodontic crowns used to treat dental anomalies or deformations to fix teeth that are in an abnormal position in the desired relationship. On orthodontic crowns, guide planes are created or exaggerated cusps are modeled with an inclination in a given direction so that when the dentition is closed, the correct relationship of the jaws is established.

Abutment crowns include all metal crowns and half-crowns. When connecting combined crowns to the intermediate part of multi-unit bridges, there is a danger of tearing off the contact wall to which the phantom part is soldered. The design of combined crowns is significantly weakened by the formation of a window filled with plastic mass.

Porcelain and plastic crowns are practically not used as support crowns.

Clinical manipulations necessary for prosthetics with artificial crowns have certain specifics due to their purpose and design varieties. The most widespread are metal stamped crowns.

More cosmetically advantageous designs with plastic, combined, porcelain crowns.

Dental crowns are permanent prostheses that restore damaged teeth or replace lost ones. Experts recommend using crowns for prosthetics if the tooth is significantly damaged - no less than 70%. If it is necessary to correct damage that is smaller in volume, fillings or dental inlays are used.

The crown restores the anatomical shape of the tooth and its functionality.

The crown resembles a cap in appearance; the design is made in a dental laboratory using individual impressions. The product can be used as an independent prosthesis, or can be used as a support for fixing clasp and bridge prostheses. The structures are widely used in the implantation process.

For prosthetic restoration of damaged and lost teeth, crowns are used as follows: indications:

• restoration of a tooth with significant destruction of its coronal part by more than half,
• pathological abrasion of enamel,
• implantation,
• restoration of the anatomical shape of the tooth,
• fluorosis,
• restoration of a tooth that has suffered from chips and cracks,
• anomalies in the shape and arrangement of teeth in a row,
• to support and protect against tooth decay with a bulk filling.

Crowns are also used in pediatric dentistry to protect teeth that are severely damaged by caries, when it is impossible to install a filling.

Contraindications for installation of dental crowns:

• tooth mobility in advanced stages of periodontal disease,
• allergy to construction materials,
• thin walls of the tooth,
• periodontal tissue diseases,
• low crown part of the tooth,
• abnormal bite.

Types of prostheses

There are several types of crowns depending on the materials and manufacturing technology:

Metal-ceramics is still the most popular type of dentures due to its optimal price-quality ratio. High strength indicators make metal-ceramics an ideal option for restoring chewing teeth.

Here you see metal ceramics on the front teeth.

A ceramic-metal product consists of a metal frame, on top of which a ceramic lining is applied. The design is bulky and heavy. Before installing the prosthesis, the tooth is depulped and ground on all sides, this is necessary for a tight fit of the crown.

Metal-ceramics can be used for the restoration of anterior teeth, but some nuances should be taken into account:

• the metal base is illuminated,
• a dark rim may appear at the junction with the gum,
• a single crown will stand out noticeably against the background of the patient’s natural teeth.

1. Ceramics

This is a modern type of crown that does not have metal elements. made according to individual prints. The product has high aesthetic qualities and is excellent for smile line prosthetics.

1. Metal-free ceramics

This is the most durable and expensive type of dental crown. For their production, zirconium dioxide is used - a material unique in its properties, which in appearance and structure is identical to natural enamel. They refract light in the same way as the natural enamel of the tooth, so often even dentists cannot distinguish a crown from a tooth. Metal-free crowns are produced using innovative technologies and modern equipment.

1. Metal-plastic

The frame of the structure is made of metal, the cladding is made of composite plastic. This is not the best option for prosthetics, as the plastic absorbs odors, quickly darkens and cracks.

1. Plastic crowns (temporary)

Such crowns have their own purpose - they cover and protect the ground tooth for the period while a permanent crown or other prosthesis is being made. Temporary crowns are lightweight, aesthetic, and help the patient avoid discomfort and get used to the prosthesis in the oral cavity.

1. Hardware

Metal crowns are rarely used now, but gold products remain popular, despite the development of technology and the introduction of new high-quality materials. Gold crowns are durable, they do not cause allergies and can withstand high chewing loads.

What are the advantages and disadvantages of crowns?

We offer you a comparative table that shows the advantages and disadvantages of different types of crowns:

Product type	Advantages	Flaws
Metal ceramics	· Affordable price. · Durability, strength. · Good aesthetic indicators.	· Before installation, a significant layer of hard tooth tissue is ground down. · The product is heavy. · The metal frame is translucent, so it is not advisable to place metal ceramics on the front teeth.
Ceramics	· High aesthetic performance. · The material transmits light, very similar in structure to enamel. · Can be installed without removing the nerve.	· Not recommended for use on bridges. · High price.
Metal-free ceramics (oxide, zirconium dioxide)	· The product is durable and lightweight. · Ideal appearance, impossible to distinguish from a real tooth. · Maximum tight fit to the tooth and gum line. · Long service life. · Can be installed on both front and chewing teeth.	The most expensive type of crowns.
Metal-plastic	· Affordable price. · Fast production.	· Outdated technology. · Service life is about 2 years. · Plastic changes color and cracks.
Metal crowns	· Durability, reliability. · Service life - up to 5 years. · Affordable price.	Due to its unaesthetic appearance, it is rarely used for front teeth. Not suitable for patients with metal allergies.

What crowns are best for chewing teeth?

Metal crowns can be placed on chewing teeth - they are reliable and durable.

What type of crown is best for prosthetic restoration of chewing teeth? Before making a choice, the dentist will take into account a number of factors:

• Metal-free ceramics will help restore and protect a damaged tooth,
• if the tooth walls are thin, in this case it is advisable to use metal ceramics,
• if the patient is limited in finances, the doctor may offer him a metal structure.

The main purpose of chewing teeth is to grind food, so when making prosthetics, the dentist’s main task is to restore this function. The ideal option in this case is metal ceramics, since the ratio of aesthetics and functionality is optimal here.
Of course, if the patient has the funds, he can install metal-free ceramics. In any case, your doctor makes the final decision.

Restoration of anterior teeth

It is possible to fix a crown on a front tooth provided that its root remains intact. If a tooth is missing, the product is fixed to the implant. You can still save money on the restoration of chewing teeth, but this option will not work with the front teeth, since they are visible when smiling and talking.

Of course, the ideal option in this case would be ceramics, or better yet, metal-free ceramics. It is durable and aesthetic. If the patient cannot afford a ceramic crown, the dentist will offer the classic – metal ceramics. This is also a good option, since high-quality and correctly installed metal-ceramic crowns on the front teeth look very good.

No, it doesn’t hurt, since all manipulations are carried out under the influence of a local anesthetic, the type and amount of which is selected individually. So that you understand what the doctor will do at each stage of prosthetics, we will introduce you to the procedure for installing crowns in more detail:

1. Preparation

This is the first and very important stage on which the quality of prosthetics depends. At the first visit, the specialist will examine your oral cavity and also send you for an X-ray. Based on the results of the examination and the image, the doctor will determine the condition of the mucous membrane and teeth and, if necessary, prescribe treatment. Plaque and stone must be removed.

To prepare a tooth for a crown, proceed as follows:

Turning is a prerequisite for prosthetic crowns, and more hard tissue is removed for metal-ceramics than for ceramics.

1. Laboratory stage

An impression is taken from the ground tooth; it is needed by a dental technician, who uses it to make a crown. During the production of the prosthesis, the patient is fitted with a temporary plastic crown on the ground stump, which protects the ground tooth and hides the defect.

1. Direct installation of a crown

First, the crown is tried on and fixed with temporary cement. If the patient feels comfortable, the product does not interfere with him or disturb the overall bite, it is fixed with permanent cement.

Why a tooth under a crown may hurt: possible complications

Pain under the crown is a common complaint of patients. But one thing is discomfort immediately after installation and several days after it, when the anesthesia wears off and one gets used to the crown. But if a patient’s tooth begins to hurt a few months, and sometimes years after the installation of a crown, this indicates the development of complications:

1. Poor preparation for prosthetics (poorly disinfected instruments, poorly filled root canals). As a result, an infection begins to multiply in the canals, which becomes the cause of the development of the inflammatory process.
2. The dentist perforated the canal walls during treatment. This can happen either due to the doctor’s fault or due to pathological curvature of the root canals. Perforation may also occur during installation in the pin channels.
3. Tool breakage. Yes, and such troubles sometimes happen in dental practice. Most often, the reason is the same curvature of the root canals. A piece of the instrument remains in the canal, and if the dentist does not notice this immediately and leaves it there, inflammation will occur over time. The tooth will have to be treated again.

Not all patients know that they can be safe from such troubles if they take an X-ray after installing the crown. In case of poor-quality treatment, everything will be visible in the picture: not completely filled root canals and the same broken piece of the instrument. In this case, the clinic must pay you for re-treatment of the tooth. If a complication appears after some time, you will have to treat the tooth at your own expense.

Price and service life

We suggest you familiarize yourself with the average cost of different types of crowns and their service life:

What determines the cost of a crown, what does the price consist of? Factors that influence pricing:

• pricing policy of the clinic: each dental clinic focuses on a specific segment of consumers,
• qualifications of the personnel: an orthopedic doctor (his payment is 20% of the cost of the prosthesis), a dental technician (his payment is about 25% of the cost of the prosthesis),
• type of materials (the most expensive is zirconium dioxide),
• the presence of a dental laboratory in the clinic (if it does not exist, the clinic will have to enter into an agreement and cooperate with a third-party laboratory, which will affect the formation of the price).

Tver State Medical Academy

Department of Orthopedic Dentistry with courses in implantology and aesthetic dentistry

Head of the department - Honored Scientist of Russia,

Doctor of Medical Sciences Professor A.S. Shcherbakov

Cast all-metal and combined crowns (metal-plastic, metal-ceramic). Conditions and indications for prosthetics. Principles and methods of tooth preparation. Double (corrected) impression with retraction of the gingival margin.

(guidelines for students)

Compiled by Ph.D., Associate Professor I.V. Petrikas

Lesson topic:“Cast all-metal and combined crowns (metal-plastic, metal-ceramic). Conditions and indications for prosthetics. Principles and methods of tooth preparation. Double (corrected) impression with retraction of the gingival margin.”

Purpose of the lesson: study the conditions and indications for prosthetics with cast all-metal and combined crowns; learn to take double impressions with silicone impression compounds, master the technique of retraction of the gingival margin.

Key words and designations:

HF – upper jaw,

LF – lower jaw,

Rg – x-ray,

Mate – cast, combined crown,

STK – light-hardening composite material,

Background knowledge.

Combined crowns- these are metal crowns that have a plastic lining on the vestibular surface, or a plastic, composite or ceramic coating on all sides.

1. The types of combined crowns are presented in Table 1.

Table 1

Types of combined crowns

Type of crown	Description of design
Metal-plastic crown (according to Ya.I. Belkin, 1947)	A stamped crown with a plastic facet on the labial surface
Metal-plastic crown according to Mathe (1961) of the classical type	Cast metal crown, where on the vestibular surface, in addition to the metal layer, there is a layer of plastic
Metal-plastic crown of fenestrated type (V.I. Bulanov, 1974)	The veneer of the combined crown is applied to the cut-out section of the vestibular surface of the cast metal crown
Metal-porcelain plastic crown (V.N. Strelnikov, O.A. Petrikas, 1998)	The basis of the structure is a metal frame, which is lined with a ceramic layer (opaque), a second ceramic layer with a mixture of plastic powder and plastic lining on all sides
Metal-ceramic crown	The metal frame of the crown is covered with ceramic coating on all sides
Metal composite crown	The metal frame of the crown is lined with laboratory STC on all sides

2. Silicone impression materials.

2.1. Two types of silicone impression materials (C-silicones and A-silicones),

2.2. Viscosity grades of silicone impression materials,

2.3. Positive properties and negative qualities of silicone impression materials.

3. Methods for retraction of the gingival margin.

3.1. Mechanical method of retraction of the gingival margin (indications and materials),

3.2. Mechano-chemical methods of retraction of the gingival margin,

3.3. Chemical methods of retraction of the gingival margin.

TASKS TO CONTROL THE INITIAL LEVEL OF KNOWLEDGE.

1. SILICONE AND THIOCOL IMPRESSION MATERIALS USED

FUCKING FOR

duplication of models,

obtaining double (corrected) impressions,

obtaining functional impressions from toothless jaws,

obtaining functional impressions with partial loss of teeth,

volumetric modeling of the polished surface of a complete denture.

obtaining an impression when relining the prosthesis,

obtaining an impression using a copper ring.

2. THE BASIS OF SILICONE IMPRESSION MATERIALS IS

sodium salt of alginic acid,

eugenol, talc, zinc oxide,

beeswax, paraffin, rosin,

silicon-organic polymers.

SILICONE AND THIOCOL IMPRESSION MATERIALS OF LOW VISCOSITY ARE USED AS

the first, main layer in double prints,

second, corrective layer in double prints.

SILICONE IMPRESSION MATERIALS INCLUDE

1) Sielast (Ukraine), 5) Stomaflex (Czech Republic),

2) Vigalen (Russia), 6) Exaflex (Japan),

3) Elastic (Czech Republic), 7) Stomalgin (Ukraine),

4)President (Switzerland), 8) 1+2+3+5+7,

POLYSULFIDE (THIOCOL) AND SILICONE IMPRESSION MATERIALS ARE ARTIFICIAL_____________________ COLD VULCANIZATION.

To retract the gingival margin in a 20-year-old patient, you will use:

retraction threads,

retractors and mechanical rings,

retraction gel

To retract the gingival margin in a 60-year-old patient with moderate periodontitis and cardiovascular pathology, you will use:

1) threads impregnated with retraction liquids,

2) retractors and mechanical rings,

3) retraction gels and pastes with adrenaline-containing substances

Installation of artificial crowns is one of the most popular procedures in modern dentistry. If there are significant defects in the tooth tissues, the elimination of which by filling or installing an inlay is impossible, you simply cannot do without an artificial crown. Loss of a tooth due to trauma or due to the incapacity of a diseased tooth is a condition that requires dental correction, since both the appearance and functional abilities of the jaw are impaired. Installing an artificial crown is a fairly quick, painless and affordable procedure that is provided today by almost every dental clinic.

What are the types of artificial tooth crowns?

The patient is provided with a huge selection of different types of artificial crowns. A competent dentist will definitely help the patient in choosing, taking into account the individual needs and capabilities of each patient. According to their purpose, all artificial crowns are divided into restorative crowns, that is, those that restore the damaged anatomical shape of a natural tooth, as well as supporting crowns, which provide fixation of bridges. Depending on the material from which the artificial crown is made, the following types of crowns are distinguished:

• metal - made from alloys of noble and base metals:

• cast - made by pouring a metal crown into a pre-prepared mold;
• stamped - crowns that are made by stamping them from special disks or sleeves;

• non-metallic - crowns that are made of porcelain or plastic;
• combined - crowns, the base of which is metal, and the lining is porcelain or plastic.

Basic requirements that artificial crowns must meet

Artificial crowns must meet specific requirements, as they can negatively affect the periodontal tissue of supporting teeth and the patient’s body as a whole. These requirements are the following mandatory conditions:

• the crown should not overestimate the bite and limit the movements of the lower jaw;
• It is strictly forbidden for the crown to fit tightly to the tissues of the tooth, especially in the area of ​​its neck;
• the crown should not violate aesthetic standards;
• the length of the crown should not exceed the depth of the periodontal sulcus;
• the thickness of the edge of the artificial crown should not exceed the volume of the periodontal sulcus;
• The width of the edge of the crown should be the same as the width of the ledge formed in the tooth.

Indications and contraindications for installing an artificial crown

The following conditions are direct indications for the installation of an artificial crown:

• destruction of hard tooth tissues as a result of a pathological process such as caries, fluorosis and others;
• anomalies in the color, structure and shape of the tooth;
• the need to restore the shape of teeth and the height of the lower third of the face in case of pathological wear;
• fixation of some types of prostheses;
• the need to splint teeth for periodontal diseases;
• temporary fixation of orthopedic and orthodontic devices;
• convergence, protrusion or divergence of teeth.

Contraindications to the installation of an artificial crown are the presence of chronic periodontal inflammation, acute periodontal inflammatory process, the presence of significant pathological mobility of teeth, as well as the presence of dental plaque.

Crown manufacturing procedure: main steps

The procedure for making an artificial crown can take a period of time from a week to a month, and consists of several stages:

1. At the first stage, odontopreparation of the tooth is carried out and the necessary impressions are taken, a model of the artificial crown is cast and it is plastermed into the occluder. Next, the teeth are modeled, stamps are obtained, and stamping is performed.
2. At the second stage, the artificial crown is tried on and its color is determined, the crown is grinded and polished.
3. The last stage is the installation and fixation of the artificial crown.

The tooth should not remain exposed for the time required to make an artificial crown. Therefore, temporary crowns are manufactured and installed, which help protect teeth from mechanical trauma and the negative influence of pathological microorganisms. In addition, a temporary crown allows you to restore the functionality of the tooth before installing a permanent artificial crown.